LIVING NERETVA - TOWARDS EU STANDARDS IN THE NERETVA RIVER BASIN, BOSNIA AND HERZEGOVINA. Living Neretva Environmental Flow Working Group (WFD-WG1)

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1 LIVING NERETVA - TOWARDS EU STANDARDS IN THE NERETVA RIVER BASIN, BOSNIA AND HERZEGOVINA Living Neretva Environmental Flow Working Group (WFD-WG1) ENVIRONMENTAL FLOW ASSESSMENT FOR THE RIVER TREBIŽAT, BiH June 2008 WWF Mediterranean Programme Office, June 2008 i

2 PROJECT: LIVING NERETVA. TOWARDS EU STANDARDS IN THE NERETVA RIVER BASIN, BOSNIA AND HERZEGOVINA (BiH) Living Neretva Environmental Flow Working Group (WFD- WG1) ENVIRONMENTAL FLOW ASSESSMENT FOR THE RIVER TREBIŽAT, BiH Financed by: Norwegian Ministry of Foreign Affairs. Project implemented by: WWF Mediterranean Programme Office in partnership with WWF Norway. Supervisor, WWF Mediterranean Programme Office: Francesca Antonelli, M.Sc. Project leader, Living Neretva: Branko Vučijak, Ph.D. Expert leader, WFD-WG1: Nataša Smolar-Žvanut, Ph.D. Expert in Hydrology: Esena Kapusovič, M.Sc. Expert in Chemistry: Zlatko Grizelj, B.Sc. Expert in Biology: Anđelka Mijatović, M.Sc. Acknowledgements: The authors are grateful to all the project team members for their intense work and genuine interest. Special thanks to Dr. Aleksandra Krivograd Klemenčič, for her contribution in phytobenthos determination and to Professor Jay O Keefee (UNESCO IHE Institute for Water Education) for his valuable comments and advice. WWF Mediterranean Programme Office, June 2008 ii

3 EXECUTIVE SUMMARY This report is one component of the Living Neretva project, funded by the Norwegian Ministry of Foreign Affairs and implemented by WWF Mediterranean Programme and WWF Norway. The main aims of the project are: to test the GEP methodology to identify the environmental flow in the selected Neretva sub-basin (river Trebižat), supported by relevant Bosnia and Herzegovina (BiH) administrations in a previous phase; to train the working group on environmental flow assessment; to collect data on river ecology, river usage and river pollution; to provide recommendations for the development of the articles in the relevant sub-laws on environmental flow, as required by the BiH Water Laws (art. 62 Water Law FBiH, art. 65 Water Law RS). The study area in southwest Bosnia and Herzegovina covers that part of western Herzegovina mainly situated in the Municipality of Ljubuški,, which is the main settlement in the area. Being part of a very specific and complex karst system, the same water flows under different names, one of which is Trebižat, the right tributary of the Neretva river. The river Trebižat and its tributaries belong to a region of arid limestone plateaus containing caves, potholes, and underground drainage systems. The water regime of the Trebižat river is affected by the extraction of its water for hydropower plants, irrigation and fish farming and by pollution. The Trebižat river flows through an area of remarkable ecological value which includes protected areas the travertine-forms around Kravice waterfall, the geomorphologic monuments of Tihaljina spring in Peć Mlini, Vrioštica spring in Vitina and the waterfalls of Koćuša, Kravice and Bučine. In the framework of the project a working group was set up composed of three experts from Bosnia and Herzegovina led by an international senior expert on Environmental Flow. The working group included expertise on hydrology and hydrogeology, biology and chemistry. The three experts were trained at the outset by the leading expert and were then provided with a detailed agenda of tasks to be implemented, including samplings and data collection. Two meetings were held (on April 8-9, 2008 and May 26-27, 2008) during which the work in progress was presented and discussed with representatives of the Federation of Bosnia and Herzegovina (FBiH) Ministry for Agriculture, Water Management and Forestry, the Republic of Srpska (RS) Ministry for Agriculture, Water Management and Forestry, Agency for Adriatic Basin from Mostar, Agency for Sava River Basin from Sarajevo, Directorate for Waters from Bijeljina. At the second workshop draft results were also presented to representatives of dams operators (three major energy production companies in BiH). During two workshops held in Ljubuški, several experts (all involved in the management of the Neretva river basin ) took part in the development of the environmental flow assessment. Using existing hydrological data and samples collected on field trips, environmental flow was assessed according to the GEP methodology at five hydrological stations. Additionally, instream ecological values and critical parameters for environmental flow assessment were evaluated. At five selected sampling sites along the Trebižat river, additional data on macrophytes, phytobenthos and physico-chemical parameters were collected and analysed. WWF Mediterranean Programme Office, June 2008 iii

4 Although there have been many negative impacts in recent years on the Trebižat river, the analyses of aquatic organisms showed their high diversity. The calculated values of environmental flow according to GEP methodology were higher than the values of 95 % of monthly minimum flow probability, as prescribed at present by the BiH Law. From this point of view adopting the GEP methodology with some changes in BiH sub-law would consequently increase values of river flows downstream of the dams. GEP methodology belongs to the so-called hydrological approach category of environmental flow assessment methods. The testing exercise carried out in the framework of this project led to the conclusion that the GEP methodology provides important advantages but also presents remarkable disadvantages. It is a rather obsolete method, which does not take advantage of globally recognized methods developed after 1990 (when the more comprehensive holistic approach began to be applied). Furthermore, testing was applied only to one river (Trebižat) in BiH so no predictions can be made regarding the results which could be expected were this methodology to be applied to other rivers in BiH. Recent developments in environmental flow assessment have improved existing methodologies and are being applied world-wide. The GEP proved to be an easy-toapply preliminary method for environmental flow assessment. An update of the method is necessary to ensure the effective protection of the ecological goods and services which rivers provide for people. These modifications would include: - Stakeholders involvement in making decisions about the priorities for the sustainable management of rivers; - The need for explicit links between the hydrology of rivers (as analysed in GEP) and the ecological components, processes and functions which are important for people. Such links provide the motivation for environmental flow assessment which is absent in the purely hydrological methods such as the GEP; - The accommodation of natural flow variability which is a key process in rivers; - The need for higher flows on which the biodiversity of flood plains and riparian areas depend. In the light of the high acceptance of the GEP methodology by BiH administrations and its easy applicability, and taking into account recent developments in the rapidly expanding field of environmental flow assessments, it is proposed to develop a second generation GEP method which would optimize the existing benefits and overcome the present limitations of the method. A final report has been delivered and validated by the national authorities with the intention of adopting the results and conclusions to support the river basin operative water management, as well as for river basin management plan preparation.although the amount or work performed in four months (March-June 2008) has been remarkable, additional efforts should be made in the future. These efforts should concentrate on i) fully developing the second generation of the GEP method; ii) filling the gaps in biodiversity data of the Trebizat river; and iii) monitoring the implementation of environmental flow, with the objective of defining the ecological status of the river. WWF Mediterranean Programme Office, June 2008 iv

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6 TABLE OF CONTENTS: 1 PROJECT BACKGROUND WHAT IS ENVIRONMENTAL FLOW FOR? INTRODUCTION General information about the impact of dams, water extraction/diversion Environmental flow definitions Approaches and methodologies for assessment Objectives of the project STUDY AREA: RIVER TIHALJINA-MLADE-TREBIŽAT Study area Geography Geology of the river and its tributaries River hydrology and morphology Ecological characteristics River pollution River usage River management Selection of sampling sites METHODOLOGY Procedure for environmental flow assessment of the Tihaljina Mlade river Objectives for environmental flow assessment GEP method (Đorđević, Dašić) Data collection Hydrology and Geomorphology Aquatic flora and fauna Physico-chemical parameters RESULTS Hydrology River ecology Fish Invertebrates Macrophytes Phytobenthos Physico-chemical parameters Identification of instream ecological values and other river values Definitionof the critical parameters for the ecological value of the river Environmental flow assessment according to GEP and environmental flow assessment including critical parameters...49 WWF Mediterranean Programme Office, June 2008 vi

7 7 RECOMMENDATIONS FOR THE DEFINITION OF SUB-LAWS ON THE APPLICATION OF ENVIRONMENTAL FLOW Gaps, advantages and disadvantages in environmental flow assessment for the Trebizat river evaluation of the GEP method Additional important criteria needed for environmental flow assessment, which are missing in the GEP methodology Recommendations for Sub-Laws in BiH legislation SECOND GENERATION GEP METHOD CONCLUSIONS Monitoring of the river ecosystem to assess environmental flow and its effectiveness Monitoring environmental flow Recommendations for future work REFERENCES APPENDICES...64 LIST OF TABLES: Table 1 Hydrological stations at V-T-M-T system...11 Table 2 Parameters of additional sampling...24 Table 3 Available data for hydrological analyses...25 Table 4 Characteristic hydrological values, HS Peć Mlini-Tihaljina source...26 Table 5 GEP-methodology-based parameters calculated, HS Peć Mlini- Tihaljina source...26 Table 6 Characteristic hydrological values, HS Peć Mlini-downstream, Tihaljina...27 Table 7 GEP-methodology-based parameters calculated, HS Peć Mlinidownstream...27 Table 8 Characteristic hydrological values, HS Tihaljina, Tihaljina...28 Table 9 GEP-methodology-based parameters calculated, HS Tihaljina...28 Table 10 Characteristic hydrological values, HS Klobuk, Mlade...28 Table 11 GEP-methodology-based parameters calculated, HS Klobuk...28 Table 12 Characteristic hydrological values, HS Grabovo vrelo...29 Table 13 GEP-methodology-based parameters calculated, HS Grabovo vrelo...29 Table 14 Results of GEP calculation for selected sections of the river...30 Table 15 Endangered habitats...32 Table 16 Fish species of the Tihaljina river...34 Table 17 Fish species of the Trebižat river (Mlade part)...34 Table 18 T1 Peć Mlini Tihaljina source...36 Table 19 T2 Peć Mlini downstream...38 Table 20 T3 Blue eye spring (Modro oko)...38 Table 21 T4 The Kavasbaša Bridge...39 Table 22 T5 Grabovo vrelo...40 Table 23 Algal species list with abundance estimations from the river Tihaljina, Table 24 Number of indicator taxa for single saprobic level...44 Table 25 Analyses of the flow at average velocity of 0,3 m/s and average depth of 0,2m...50 WWF Mediterranean Programme Office, June 2008 vii

8 LIST OF FIGURES: Figure 1 -Hydrogeological map of western Herzegovina...10 Figure 2 - Hydrography of the V-T-M-T catchment with hydrological stations...12 Figure 3 Hydrography of the Tihaljina river...12 Figure 4 Hydrography of the Mlade river...13 Figure 5 Hydrography of the Trebižat river...13 Figure 6 Hydrological stations and sampling sites along a selected section of Tihaljina and Mlade...17 Figure 7 procedure for environmental flow assessment...19 Figure 8 Hydrograph of Mlade river at HS Klobuk, Figure 9 Bray-Curtis coefficient of similarity for the sampling sites in the Tihaljina river...45 Figure 10 1-Gloeocapsa sp., 2-Phormidium sp., 3-Achnanthes sp., 4- Ulothrix sp., 5-Nitzschia fonticola...46 LIST OF APPENDIX: Appendix 1 Hydrology of HS Pec Mlini Tihaljina source (No 8) Appendix 2 Hydrology of HS Pec Mlini downstream (No 9) Appendix 3 Hydrology of HS Tihahljina (No 10) Appendix 4 Hydrology of HS Klobuk (No 11) Appendix 5 Hydrology of HS Grabovo vrelo (No 12) Appendix 6 Hydrology of HS Grabovo vrelo (No 24) Appendix 7 Physico-chemical parameters Appendix 8 environmental flow assessment with including critical parameters WWF Mediterranean Programme Office, June 2008 viii

9 1 PROJECT BACKGROUND This report is the continuation of the first phase of the project Living Neretva - Towards EU-standards in the Neretva river basin running from July 2006 to December Three working groupswere set up under the supervision of the relevant BiH authorities, to adapt BiH environmental protection practices to the standards of key EU environmental acquis communautaire, namely the Water Framework Directive (WFD) and the Habitat Directive (HD), During the first phase a working group was established to assess different methods for environmental flow (EF) calculation and, in cooperation with the BiH water authorities, to select one method to be applied to BiH rivers. The analysis led to a tentative selection of the socalled GEP method. This report is the direct follow up of the first phase of the Living Neretva project and embodies the work of a group of national experts led by an expert in environmental flow, with relevant international experience in environmental flow assessment. To provide the necessary expertise for environmental flow calculation, three BiH experts in hydrology and hydrogeology, biology and chemistry were selected. The biologist and chemist were required to be familiar with the pre-selected area of Trebizat. The working group was at first trained by the leading expert and then provided with a detailed agenda of tasks to be implemented, including samplings and data collection. There were two meetings (held on April 8-9, 2008 and May 26-27, 2008) during which the work in progress was presented and discussed with representatives of the FBiH Ministry for Agriculture, Water Management and Forestry, the RS Ministry for Agriculture, Water Management and Forestry, the Agency for the Adriatic Basin from Mostar, the Agency for the Sava River Basin from Sarajevo, the Directorate for Waters from Bijeljina. Draft results were also presented to representatives of dams operators (three major energy production companies in BiH) during the second workshop The final report is currently being validated by the authorities mentioned above with the intention of adopting the results and conclusions to support the operative water management of the river basin, as well as for preparation of the plan for its management. WWF Mediterranean Programme Office, June

10 2 WHAT IS ENVIRONMENTAL FLOW FOR? Flow for nature should not be seen as being in competition with flow for people. Only a short term approach can justify this damaging attitude. On the other hand, the long term availability of water resources is a prerequisite for healthy and wealthy communities and it depends on the wise use of resources. This wise use relies on balancing nature s needs with human needs. The environmental flow assessment should be seen as a tool for finding this balance and ensuring a long-term and good quality water supply The indicators used in environmental flow assessment process are the endangered habitats and species (ecosystems) that should be seen as a sort of thermometer of the health of the rivers and their capacity to provide the goods and services that water users need, for hydropower, industry, domestic supply, or the agriculture sector. The bottom line is that a healthy riverine ecosystem sustains livelihoods. Environmental flow is a tool to balance water needs for healthy ecosystems and water needs from different users. WWF Mediterranean Programme Office, June

11 3 INTRODUCTION 3.1 General information about the impact of dams, water extraction/diversion The alteration of the water flow downstream of dams is one of the most stressful factors influencing the aquatic and riverine ecosystem. These effects are often related to the fragmentation of water habitats (Maddock et al., 2005), toxic matter in sediments and water, invasive alien species and pollution (Biggs & Close, 1989). When to analysing the effects of damming, water extraction and diversions, one needs to deal with all the factors in a connected manner. The effects of damming on hydrological parameters are to be found in the changed dynamics of flow below dams, duration and frequency of water flow, and reduction of velocity and temporal uniformity of water flow. The sediments that are not transported are deposited as alluvial deposits (Mikoš, 1989). Anthropogenic effects, such as water channel regulations, may cause reduction in deposition, impoundments and denudation/removal of fine sediment. During periods of low flow, fine sediment accumulates in the watercourses (Milhous, 1998) and deposition of organic matter increases, particularly in river pools and in reaches where the water is impounded (Everard, 1996). The size and structure of aquatic habitats influence the community of aquatic organisms (Aadland, 1993, Maddock 1999, Gehrke & Harris 2000, Maddock et al. 2004). Several methodologies that have been developed world-wide assess the effects of an increased human exploitation of water sources on aquatic habitats (Maddock & Bird, 1996). Results demonstrate significant differences in the mesohabitats of unregulated and regulated reaches. Unregulated reaches are dominated by fastflowing and turbulent types of mesohabitats while in regulated reaches of rivers, slow-flowing types of mesohabitats are present (Smolar-Zvanut et al, 2007). Reduced flows due to river regulation also significantly reduce the size of mesohabitats, alter their hydraulic character, and affect the longitudinal distribution of types by creating greater habitat fragmentation (Maddock et al, 2007). The extraction of water results in most cases in changes to its physico-chemical parameters, reduction of biodiversity of aquatic and riparian flora; the changed local conditions enable the increase in the biomass of particular species, which may cause environmental problems (Biggs, 1996). 3.2 Environmental flow definitions The increasing demand for water is degrading rivers worldwide, resulting in a loss of the vital goods and services they provide. Nowhere is the problem more urgent than in developing countries. Many of these countries acknowledge that environmental protection must be a component of their management of water but have limited data and understanding of their aquatic ecosystems with which to achieve this (King et al. 2003). Dams are often the most significant and direct modifiers of natural river flows. They are therefore an important starting point for the implementation of environmental WWF Mediterranean Programme Office, June

12 flows. Downstream releases from dams are determined by the design of the dam whether to pass water through, over or around the dam. The operating policies and rules determine the amount and timing of releases for environmental flows. The design and operations of other infrastructure such as distribution canals and weirs, can also contribute to establishing environmental flows (Dyson et al, 2003). Environmental flow is the term for the amount of water needed in a watercourse a river, wetland or coastal zone to maintain healthy, natural ecosystems and their benefits where there are competing water uses and where flows are regulated (Dyson et al, 2003). The main goal of environmental flow is, according to the Water Framework Directive, to maintain the ecological status of the structure and function of aquatic and riparian ecosystems at least until The water laws in BiH (WL, 2006) emphasise that environmental flow should be determined on the basis of the research that has been carried out, in accordance with the methods for its determination, defined in the sub-legal act, and should take into consideration the specific characteristics of the local ecosystem and the flow s seasonal variation. The Water Law establishes the legal basis for sustainable water resource management. Until the environmental flow sub-legal act is enforced, the environmental flow should be established, on the basis of the hydrological characteristics of the water body for a particular season, as the monthly minimum average flow occurring with 95% probability (WWF project Living Neretva, Environmental Flow Group report, 2007). 3.3 Approaches and methodologies for assessment Environmental flow assessment requires the integration of a range of disciplines, including engineering, law, ecology, economy, hydrology, political science and communication. It also requires negotiations between stakeholders in order to bridge the different interests that compete for the usage of water, especially in those basins where competition is already fierce (Dyson et al, 2003). According to Tharme (2003), the main attributes of the specific approach used to define environmental flow can be categorised into four groups: 1) Hydrological methods: simple tables based on hydrological indices; 2) Hydraulic rating methods: fieldwork and rapid desk-top analysis using a combination of hydrological, hydraulic or ecological data; 3) Habitat simulation methods: habitat modelling that determines the relationship between flow and habitat availability; 4) Holistic methodologies: functional analysis that considers a wide range of ecological and hydrological aspects of river systems and often includes the use of panels of experts. A review of global approaches to environmental flow assessment was presented by Tharme (2003). The methods in groups 1) and 2) described above provide a rapid WWF Mediterranean Programme Office, June

13 appraisal of environmental flow requirements and are useful for initial appraisal purposes. They tend to focus on the hydrological and hydraulic parameters of rivers that are deemed to be ecologically important in very generic terms, without a detailed knowledge of how these parameters specifically determine the ecological status of the river. A major criticism of hydrological methods is their exclusion of any explicit consideration of actual habitat requirements, water quality and other geomorphological factors. The methods in groups, 3) and 4) overcome this problem by considering the site-specific linkages between flow, morphology and ecology in much more detail and hence are deemed to be more scientifically robust and defensible. However, they normally have much greater field data requirements, demand personnel with a broad range of expertise and require considerably more time to be implemented (Maddock I, 2008, personal comm.). A high number of methodologies presenting some combination of hydrological, habitat-discharge and/or partial holistic approaches have been developed and applied across the world. According to Arthington and Zalucki (1998), approaches to environmental flow assessment can also be divided into the following groups: 1. Methods addressing flow requirements for geomorphological purposes 2. Methods addressing flow requirements for wetland, riparian and floodplain vegetation 3. Methods addressing flow requirements of fish 4. Methods addressing flow requirements of aquatic invertebrates Historically, instream flow studies have focused on determining the low-flow conditions required to maintain particular instream values, because low-flow periods are the time of greatest competition for the limited amount of water that is available, and a time when the river ecosystem is most under stress. However, several aspects of a river s flow regime may influence its ability to maintain particular instream values. These may be summarised as follows (Jowett and Biggs 2006): Large floods Smaller floods and freshets, with a frequency of a few times each year Low flows Annual flow regime Flow variability. The main ecologically relevant components of flow regime are: Magnitude of discharge Frequency of occurence Duration of given flow conditions Timing or predictability of flow Flashiness of flow River management requires scientifically-sound operational tools for an evaluation of environmental flow that meets instream, riparian and floodplain needs (Petts and Maddock, 1995). The basic components of an environmental flow strategy should include the following flows (Petts, 1996, Erskine et al, 1999): channel maintenance flows habitat maintenance flows minimum flows that preserve aquatic and riparian ecosystem minimum acceptable flows that enable maximum habitats for target species WWF Mediterranean Programme Office, June

14 flows that enable the seasonality of flood flows. 3.4 Objectives of the project The objectives of this project derive from the conclusions of the first phase of the Living Neretva Environmental Flow working group, finalized in The main aims of this project were: to test the selected GEP methodology for the calculation of the environmental flow in a selected pilot area of Neretva, the river Trebižat;. to increase the capacity of a selected number of experts on environmental flow assessment; to collect data on river ecology, river use, and river pollution; to develop recommendations for the preparation of relevant sub-laws on environmental flow, as required by BiH Water Laws (art. 62 Water Law FBiH, art. 65 Water Law RS. WWF Mediterranean Programme Office, June

15 4 STUDY AREA: RIVER TIHALJINA-MLADE- TREBIŽAT 4.1 Study area The study area in southwest Bosnia and Herzegovina covers that part of western Herzegovina mainly situated in the Municipality of Ljubuški, which is the main settlement in the area. A Broad area of western Herzegovina is represented by the dominance of well developed Karst formations and phenomena, with specific hydrodynamic functioning. The most interesting part under this study was the middle one, with its water courses flowing from the northwest toward the Neretva river, which flows from the southeast but assumes a sharp southwestern flow through the Karst region. Ljubuški also has several karst-specific arable lowlands ( poljes ): Ljubuško polje, Veljačko polje, Vitinsko polje, Rastok and Beriš, irrigated by the Tihaljina Mlade Trebižat river system, with two beautiful waterfalls Kravica and Koćuša. On the basis of the field trip and the visit to different sections of the Tihaljina-Mlade- Trebižat river and according to exisiting hydrological data, environmental flow was assessed for the section of the Tihaljina and Mlade river, from the source of Tihajlina (gauging station Peč Mlini uzvodno / nizvodno) to the gauging station Grabovo vrelo (Mlade); that means that environmental flow was assessed for the Tihaljina river and for a part of the Mlade river. Environmental flow was evaluated for the following gauging / hydrological stations (HS): 1. HS Peć Mlini Tihaljina source 2. HS Peć Mlini downstream (Tihaljina) 3. HS Tihaljina (Tihaljina) 4. HS Klobuk Kavasbašin most (Mlade) 5. HS Grabovo vrelo (Mlade) A description with photos of the hydrological stations isin Appendix 1 Appendix Geography Trebižat is the right tributary of the Neretva river, which flows about 50km from its source in Peć-Mlini (Grude) to its mouth into the Neretva river (Struge, Čapljina). However, being part of a very specific and complex draining system of the karst of western Herzegovina, the same water flows under different names. The section from Peć-Mlini to Klobuk is known as Tihaljina river, that from the source Klokun to the inlet into the water course Vrioštica is called Mlade, and finally, that from Humac to the inlet to the Neretva river, is called Trebižat. The avalilable elevation from the source in Peć-Mlini (about m.a.s.l.) 1 to its mouth into the Neretva river (about 8 m.a.s.l.) is around 120m. 1 Earlier altitude of the source was around 245 m.a.s.l., at Ravlica cave, much higher than the current one WWF Mediterranean Programme Office, June

16 Going upstream, looking from the Ljubuško Polje at the Imotsko-Bekijsko Polje, we will meet the waters of the Trebižat called by five names: Matica Vrlika Tihaljina Mlade Trebižat. Moreover, looking at the upper horizons, it becomes a river with the names Ričina Suvaja Sija - Matica - Vrlika - Tihaljina - Mlade Trebižat. The total orographic catchment area is around 1200km 2, including about 90km 2 of the Imotsko-Bekijsko polje area. It is necessary to note that the hydrological watershed is hard to define correctly, because of the Karst phenomena described above. Climate conditions Although Bosnia and Herzegovina is largely cut off from the climatic influence of the Mediterranean by the Dinaric Alps, Herzegovina is more similar to the Dalmatian mountains. Being on the border between Continental and Mediterranean climate, western part of Herzegovina is in a moderate continental climate zone, with abundant precipitation, but hot in summer. The coldest month is January, averaging 6 C, and the warmest month is July, averaging about 26 C. A relatively dry season is from June to September. The remainder of the year is wet, with the heaviest precipitation between October and January. Historic heritage of the river Due to its climate with abundance of sun and precipitations, this area has been attractive for the humans since a long time ago. The system of surface watercourses is one of the most significant. For example, Romans conquered Illyrians in the 1 st century and built military and civil settlements. As part of one of the military buildings for the numerous Romans legions, a bathing sauna has been found, with an underground system of heating (hypocausis). The existence of numerous civil agricultural estates (known as villae rusticate) has not yet been investigated. During the Austro-Hungarian period, an improved system for the Ljubuško polje was built. Irrigation systems for agriculture production, as well as the usage of water power for numerous water mills, have been common practice in this area for a long time. The beauty of the Trebižat river is well known: it includes numerous water sources surrounded by beautiful nature (source of Tihaljina, Klokun, Modro oko, Vrioštica) and wonderful waterfalls like Koćuša and Kravica. Kravica waterfall runs for 100 meters and drops an impressive 25 meters. Demography There has been no precise data regarding Bosnia and Herzegovina's population since the last war. The UNHCR conducted an unofficial census in 1996, but the data have not been recognized. Generally, according to the latest data available, the ratio between the urban and rural population is 60 to 40. This resettlement trend has led to the complete decline of many rural settlements and the appearance of underpopulated areas. A false image of a highly urbanized country and of heavy pressure on the environment is thus created. 2 2 Governments of the Federation of Bosnia and Herzegovina and Republika Srpska, 2003, National Environmental Plan NEAP WWF Mediterranean Programme Office, June

17 The problems of both poverty and social issues in Bosnia and Herzegovina have been recently comprehensively examined. 3 The solution, it was concluded, lies precisely in economic development, which implies the revitalization of the country s economic capacities and a return to pre-war levels of employment and sustainable rural development. 4 According to a 1991 census, the number of inhabitants in the Municipality of Ljubuški was 28,340, including Ljubuški with about 5,000 citizens. In the related area of 289km 2, the specific density was 98 inhabitants per km Geology of the river and its tributaries The river Trebižat and its tributaries belong to a region of arid limestone plateaus with caves, potholes, and underground drainage, as a result of natural processes through long geological periods: rain and snow falling in winter absorb carbon dioxide out of air and soil, turning it into weak carbonic acid. This is a consequence of their effects on soluble rocks (limestone and dolomite). The uplands are often bare and denuded (the result of deforestation and thin soils), but, between the ridges, depressions known as poljes are covered with alluvial soil that is suitable for agriculture. As rainfall water sinks through cracks very fast, the network of surface water course is poor, sometimes represented by temporary water courses, while Karst formations (sinkholes, zones of sinkholes, estavelles) are present with specific hydrodynamic functioning. The most significant is the characteristic of a high water permeability, often represented by a complicated network of underground channels. Figure 1 shows zones of high and low permeability, as well as the directions of underground water courses, researched with tracers (Slišković). 3 «Poverty Assessment in BiH» is the result of a survey conducted on living standards in BiH for the year 2001 by a team of experts from the World Bank in cooperation with representatives from the Institutes for Statistics of RS and FBiH and the BiH Agency for Statistics. 4 The analysis of the system of settlements shows that there are about 1,500 sub-municipal centres with inhabitants that possess the resources that could be used primarily for healthy food production. WWF Mediterranean Programme Office, June

18 Figure 1 -Hydrogeological map of western Herzegovina 4.3 River hydrology and morphology When talking about the Trebižat river from a hydrological point of view, it is important to stress the complexity of the natural hydrodynamic water regime of the broader area of western Herzegovina. As already mentioned, if we are looking from the Ljubuško Polje towards the Imotsko-Bekijsko Polje, we will see the waters of the Trebižat, which has four names: Vrlika Tihaljina Mlade Trebižat (watercourse V-T-M-T). The total length of the V-T-M-T watercourse from the Opačac source (Vrljika) to the mouth into the Neretva river (Trebižat) is around 70km. The orographic catchment area is in total around 1200km 2, including about 90km 2 of the Imotsko-Bekijsko polje area. It is necessary to note that the hydrological watershed is hard to define correctly because of the Karst phenomena described above. A general preview of the network of the surface watercourse system V-T-M-T is shown in Figure 2. The hydrological stations within the V-T-M-T system are shown in Table 1. WWF Mediterranean Programme Office, June

19 Table 1 Hydrological stations at V-T-M-T system No HS Watercourse Catchment 1 Kamenmost Vrljika 2 Biočići Vrljika 3 Rakitovac Vrljika 4 Drinovci Ponor Šainovac 5 Drinovci Plavilo 6 Drinovci Jezero Nuga Adriatic Sea Adriatic Sea Adriatic Sea Adriatic Sea Adriatic Sea Adriatic Sea Coordinates latitude longitude Altitude HS «0» , , , , , ,91 7 Brzotok Vrljika/Tihaljina Neretva Peć Mlini uzv Tihaljina Neretva ,39 9 Peć Mlini nizv Tihaljina Neretva ,53 10 Tihaljina Tihaljina Neretva ,75 11 Klobuk Mlade Neretva ,74 12 Grabovo vrelo Mlade Neretva ,90 13 Koćuša Veljaci Mlade Neretva ,18 14 Grab Mlade Neretva ,76 15 Humac Trebižat Neretva ,88 16 Stubica Trebižat Neretva Studenci Trebižat Neretva ,81 18 Donji Vinjani Velika Udovica Vrljike ,34 19 Donji Vinjani Mala Udovica Vrljike ,34 20 Grude Grudsko vrelo J. mora ,73 21 Farkašev most Prispa J. mora ,94 22 Baran Prispa J. mora ,89 23 Poljana Vrelo Klokun Tihaljine ,56 24 Grabovo vrelo Grabovo vrelo Mlade ,19 25 Kapel Mahala Studena Mlade Parilo Brza voda Kanal Mlade ,54 27 Vitina Vrioštica Mlade ,65 28 Studenci Studenčica Trebižata Rel 24,00 WWF Mediterranean Programme Office, June

20 Figure 2 - Hydrography of the V-T-M-T catchment with hydrological stations The left tributaries to the Tihaljina river are short watercourses: Krupa, Nevidin, Jakšenica, Nezdravica. From the right side, the Zloriba, the Meljava and some small watercourses around the Klobuk source flow into the Tihaljina, Figure 3. Figure 3 Hydrography of the Tihaljina river The main left-tributary to the Mlade is the Vrioštica, as well as a creek forming at D.Proboj. The temporary watercourse Studeni potok flows into the Mlade from the right side, close to the Koćuša waterfall, Figure 4. WWF Mediterranean Programme Office, June

21 Figure 4 Hydrography of the Mlade river The main left tributary of the Trebižata is the Studenčica, which collects the temporary water courses Lukoča and Stube, Figure 5. Figure 5 Hydrography of the Trebižat river WWF Mediterranean Programme Office, June

22 4.4 Ecological characteristics Ecoregion The Herzegovina region includes the entire area of the river Trebižat. This region is characterised by the belt of the Mediterranean ecoregion. The region includes the area of the east coast of the Adriatic karst, which stands as a separate Eastern Adriatic sector of the Adriatic province. As to climate, this is an area under varying influence from the Mediterranean climate, characterised by mild and considerably short, rainy winters and dry, hot summers. There are significant differences between the parts of the Adriatic province that directly adjoin the sea, and those more or less distant from it, horizontally and/or vertically. The differentiation is between the Eumediterranean zone and sub-mediterranean zone (including in a broader context the Mediterraneanmontane vegetation belt). Sub-mediterranean zone The Herzegovina area is in the sub-mediterranean zone that, includes the belt of decidous vegetation which is a direct continuation of the evergreen zone of the Eumediterranean coast, and the Mediterranean-montane belt of deciduous vegetation situated at higher altitudes. Compared to the climate of the Eumediterranean zone, this zone has relatively greater amount of precipitation. This fact and the relatively cold winters, cause the break in the vegetation, that is, its deciduous habit. The lower belt of the sub-mediterranean zone is characterised by the zonal forest association Carpinetum orientalis adriaticum (Carpinion orientalis alliance, order Quercetalia pubescentis, class Querco Fagetea). In the large part of the Submediterranean coast of the east Adriatic, the association Carpnetum orientalis adriaticum has developted in the form of bigger or smaller and thinner shrubs or underbrush. The higher Mediterranean montane belt harbours in the hinterland the zonal forest association Carpinetum orientalis adriaticum. Due to degradation, these Sub-mediterranean forests have turned into specific, permanent anthropogenic forms dry grasslands and rocky pastures of the order Scorzonero Chrysopogonetalia. Protection status of the river According to BiH Environmental protection law, protected environmental landmarks on the Trebižat River are: The travertine-forming around the Kravice waterfall, which is one of the geological monuments of nature, geomorphologic monuments: the Tihaljina spring in Peć Mlini, the Vrioštica spring in Vitina, and the waterfalls Koćuša, Kravice and Bučine. WWF Mediterranean Programme Office, June

23 4.5 River pollution In the summer when the water level decreases the water quality can be lower, due to the presence of fecal pollution, which is connected with the fact that the underground flow most probably collects the wastewaters from the counties of Grude and Posušje. River pollution can also be caused by agriculture, urbanization and lack of wastewater treatment plants. One of the reasons for the high concentration of sulphate in the Modro oko tributary could be the natural dissolving of the alabaster substrate when the water flows underground. 4.6 River usage Apart from the unique Karst hydrogeology, anthropogenic processes, with the existence of numerous hydro-technical buildings that affect the water regime, are also significant in this area: - Water catchments were built for various purposes, especially for agriculture. In the sub-mediterranean climate the arable terrain (in the Karst polje) needs water for irrigation, especially during the warm season. As a result, a surface network of artificial irrigation water streams is highly developed, with the first one built close to the Tihaljina source; - Close to the mouth of the Grabovo vrelo there is a water diversion for a fish farm, as well as for irrigation purposes, which influences the flow regime of this section of the Mlade. The remaining water returns to the Mlade at the river section downstream of HS Grabovo Vrelo (river Mlade); - The water reservoirs Ričica (in 1987), Tribistovo (in 1990), and Rastovača (water supply, irrigation, flood defence) were built along the upper part; - The underground tunnel Pećnik was built in 1950, together with the tower gate (Kula zatvaračnica), to defend the Imotsko polje from floods, e.g. the high water evacuation from the natural temporary reservoir Nuga, during the wet season; the surface part of the evacuation system is represented by a concrete-fast waterway (brzotok) that flows into the Tihaljina river; - The HPP Peć Mlini, located downstream of the Tihaljina source, has been functioning since HPP Pec Mlini is a derivation type of hydropower plant, connected with the water reservoir/lake Nuga by a pressure tunnel (diameter 3.6m), then a surface pipe (diameter 2.6m) and with the engine room at Drinovci / Pec Mlini. The water intake from the Nuga lake for the purposes of HPP Pec Mlini also affects the water quantities of the Tihaljina source, because the gate at the Sainovac sink has been in function since 2004 to keep the water in the Nuga reservoire. 4.7 River management The Agency for the Adriatic Sea catchment (Mostar) is responsible for the Neretva river management, including the river Trebižat, in the BiH Federation. Some of the main responsibilities of the Agency are as follows: - Data collection on water resources, including establishment and maintainance of the Information System; WWF Mediterranean Programme Office, June

24 - Organization of water quantity and water quality monitoring; - Preparation of reports on the state of the water; - Preparation of the River management plan (to 2012); - Preparation of technical documentation on particular water management issues, in accordance with the Water Law; - Flood-protection plan preparation; - Water license issue. In 2007, Elektroprivreda HZ HB Mostar prepared a basic document on the hydrological, land surveying and power generation basis for the potential locations of mini hydropower plants (mini HPP) at the river system Tihaljina-Mlade Trebižat (T- M-T). Five potential locations are recognized: mini HPP Modro oko, mini HPP Klokun, mini HPP Koćuša, mini HPP Kravica and mini HPP Stubica. 4.8 Selection of sampling sites Environmental flow assessment heavily relies on the knowledge of the structure and function of the river under investigation. At the time when the team were collecting existing data on river ecology and river physico-chemical data, it was found that many data were missing. As a result, it was decided to sample additional parameters, such as macrophytes, phytobenthos and selected physico-chemical variables. Macrophytes are very important primary producers in the Trebižat river and phytobenthos is one of the main groups of organisms with an important function in travertine formation. The objective was to evaluate water pollution of the river Tihaljina through selected physico-chemical parameters. These data have helped assess the river status, the ecological values of the river and select critical parameters for the environmental flow assessment. The sampling sites were selected between the source of the Tihaljina to the hydrological station Grabovo vrelo. To get more information about the structure and function of the river ecosystem 5 sampling sites were selected (Figure 6): T1 near the HS Peč Mlini Tihaljina source (8) T2 near the HS Peč Mlini downstream (9) T3 at the Modro oko source T4 near HS Klobuk (11) T5 near HS Grabovo vrelo (12) The sampling site T3 was selected at the inflow of the Tihaljina, because it is known it contain high values of sulphates. WWF Mediterranean Programme Office, June

25 Figure 6 Hydrological stations and sampling sites along a selected section of Tihaljina and Mlade WWF Mediterranean Programme Office, June

26 5 METHODOLOGY 5.1 Procedure for environmental flow assessment of the Tihaljina Mlade river Although the main objective of the project was environmental flow calculation only according to the GEP methodology, we followed the main idea that an environmental flow must maintain the river ecosystem. This means that the structure and the function of the ecosystem must be known. As a result of this assessment, the team intends to stress the need for additional criteria with respect to the GEP. These additional criteria play an important role in the holistic approach of environmental flow evaluation, and this was the motive for the collection of additional biological and physico-chemical parameters of the river, that are otherwise unnecessary when applying only GEP methodology. The working group used a process for calculating environmental flow for the river section consisting of 8 steps, represented in Figure 7. This project was not intended to reach step 8 (monitoring) because of its limited duration, but it is hoped that monitoring will be incorporated into the next phases of the project. WWF Mediterranean Programme Office, June

27 2. Identify out-ofstream uses of the river, pressures and impacts 1.Data for the river Trebižat 3. Identify and assess river and riparian ecosystem the values 4. Identify river values that are to be preserved 5. Determine the environmental flow (ecological) objective 6. Identify the critical factors 7. Assessment of environmental flow: GEP and 8. Monitoring: Does the environmental flow meet, sustain the river management objective? No Figure 7 procedure for environmental flow assessment In the case of this pilot environmental flow assessment in BiH, a critical constraint in the procedure was the lack of data on river ecology. WWF Mediterranean Programme Office, June

28 5.2 Objectives for environmental flow assessment In general, the overall goal of an environmental flow assessment is to ensure that river ecosystems are healthy and can provide goods and services for the benefit of people. The specific objectives for environmental flow assessment in rivers are: - to protect aquatic and riparian ecosystem from deterioration - to improve /preserve habitats for aquatic flora and fauna - to restrict water extraction/diversion during low-flow periods - to protect habitats, especially for endemic and endangered species. It was impossible to define more detailed objectives, such as maintaining good ecological status or good ecological potential of the river, for the lack of ecological data mentioned above, and because the thresholds for ecological classes (required by the new BiH water laws) are not yet developed in BiH. 5.3 GEP method (Đorđević, Dašić) The application of the GEP methodology is based on three parameters: (1) average multiannual flow on the dam profile, eg. location of water diversion ( Q ), (2) min. monthly monthly-minimum low-flow 95% exceedence probability ( Q 95% ), (3) monthlyminimum low-flow 80% exceedence probability ( Q min.monthly 80 & ). If multiannual series of daily flows are available, instead of minimal monthly flow ( Q min.monthly 95 % ) and Q.monthly min & ( 80 ), adequate values of 30-day low flow with the same exceedence min.( 30 probability (Q ) 95% ) and ( Q ) can be used 5. When all mentioned data are min.(30) 80% available, basic principles are summarized in a clear rule that defines the GEP methodology: The guaranteed ecological flow (GEP flow Q ecol. gar ) adoption is as follows: (1) During the cold season (October-March), the guaranteed Q ecol. gar should be chosen as the value of the monthly-minimum low-flow 95% exceedence probability ( Q min.monthly 95 % ), e.g. 30-day low-flow with the same exceedence min.( 30 probability (Q ) 95% ), but that value should neither be less than 0,1 Q, nor higher than 0,15 Q. That means that Q ecol. gar for the cold season should be chosen on the basis of the equation: 5 Alternatives are given by operational reasons. Certainly, it is better if the data on the 30-day low-flow appropriate exceedence probability are available, because that is more in accordance with the physics of low flow phenomena: extremely low flow periods defined as the year-low flow of 30-day duration in min.( 30) continuity, can cover parts of two months. However, insisting only on flows (Q 95% ) and min.( 30) (Q 80% ) would not make sense, because the daily flows often are not available.. As a rule, the usage of the monthly-min low-flow instead of the 30-day low-flow issues slightly higher values. WWF Mediterranean Programme Office, June

29 Q ecol.gar. = Q 0.1 Q ili Q 0.15 Q min.monthly 95% min.(30) 95% for for for Q 0.1 Q < Q Q ili Q min.monthly 95% min.monthly 95% min.monthly 95% ili Q min.(30) 95% min.(30) ili Q95% min.(30) 95% 0.1 Q < 0.15 Q 0.15 Q (2) During the warm season (April-September), the guaranteed Q ecol. gar should be chosen as the value of the monthly- minimum low-flow 80% exceedence probability ( Q min.monthly 80 % ), e.g. 30-day low-flow with the same exceedence probability ( Q ), but that value should not be less than 0,15 Q. e.g. it min.(30) 80% should be higher than 0,25 Q. That means that Q ecol. gar for the warm season should be chosen on the basis of the equation: Q ekol.gar. = Q min.mes 80% 0.15 Q ili Q 0.25 Q min.(30) 80% for for for Q 0.15 Q < Q Q ili Q min.mes min.(30) 80% 80% min.mes min.(30) 80% ili Q80% min.mes min.(30) 80% ili Q80% 0.15 Q < 0.25 Q 0.25 Q If the values of the GEP flow issued by a defined low-flow exceedence probability are beyond the amplitude defined by the above rules and equations (1) and (2), limiting values should be chosen. (3) If the water course is used for specific ecological or recreational requests and goals, the values issued on the basis of the above rules and equations could be increased as follows: up to 15% for the cold season, up to 30% for the warm season. A special analysis/justification of the increased value is needed in such a case. (4) The values of the GEP flow issued for the cold season could be treated as constant, but, if needed, a certain variation is possible (a certain increase of flow in March, during the reproduction period for some fish). (5) The Values of the GEP flow for the warm season are averages. The meeting of special needs of ichtiofauna and other organisms is required. In critical periods of reproduction, discharge values need to be increased in accordance with eventual requests by the authorities responsible for ecological protection and fisheries. A decrease is possible during proper hydrological situations when flows are favorable, but the values of the flow downstream should not be less than the discharges during the cold season. (6) The flow released for these purposes is not energetically lost. Small turbines can be applied at such outflow, which will use that discharge. But there is an obligation for such outflow to have separate flow gates that will enable release of water even when the turbine is out of order or is under maintenance. 5.4 Data collection Hydrology and Geomorphology WWF Mediterranean Programme Office, June

30 The study Tihaljina Mlade Trebizat was carried out by «Elektroprivreda» HZ HB, and prepared by the Federal Hydrometeorological Institute in The main task of the study was i) to assess the hydrological parameters for the river system Vrljika Tihaljina-Mlade-Trebižat and ii) to assess the flow regime including its spatial and temporal distribution for the period during which data were collected Aquatic flora and fauna Existing data Previous research was carried out in 1963 and 2003 and results are presented in the following papers: Matoničkin, I. & Pavletić, Z Sudjelovanje pojedinih životinjskih i biljnih skupina u izgradnji životnih zajednica na sedrenim i erozijskim slapovima Bosne i Hercegovine. Iz Biološkog instituta i Instituta za botaniku Sveučilišta Zagreb. This paper mentions the biological communities (flora and fauna) that are involved in the building of the travertine-forming waterfall Kravice on the Trebižat River. Bogut, I., Pavličević J., Ivanković, S., Petrović, D., Kvalitativni i kvantitativni sastav ihtiofaune rijeke Trebižat. Znanstveno stručni simpozij s međunarodnim sudjelovanjem Voda u kršu slivova Cetine, Neretve i Trebišnjice, Zbornik radova, Neum.This paper is referred to further in the chapter titled Ihtiofauna Additional sampling done by the project Macrophytes Field research was carried out during 2007 at sampling sites T4 and T5 for the Ph.D. thesis of a working group member, and at sampling sites T1, T2 and T3, in April 2008 for the Living Neretva project. The main disadvantage during the time of sampling was a quite high water flow. The families of macrophytes are determined by using standard keys and iconography ( FIORI , 1933; TUTIN et all ; TRINAJSTIĆ ; PIGNATTI 1982; DOMAC 1994; BURNIE 1995; DELFORGE 1995, 2001; BLAMEY i GREY WILSON 1998 ). The plants are collected and stored in the Department of Biology of the Faculty of science and education, at the University of Mostar. Phytobenthos Five samples of phytobenthos were collected in April 2008 from the river Tihaljina within the framework of the project. The samples were brushed from the surface of stones and rocks with a razor and also squeezed out of water moss. The samples were immediately preserved in a 4% formaldehyde solution. Each of the samples was WWF Mediterranean Programme Office, June

31 treated with concentrated HNO 3 in order to determine Bacillariophyceae species (APHA, 1992). Species were determined by a light microscope Nikon Eclipse E400 (magnification 1000 ) and the following identification monographs: Krammer & Lange-Bertalot ( ), Hindák et al. (1978), Hindák (1996), Komárek & Anagnostidis (1998, 2005). Relative abundance was estimated according to Pantle & Buck (1955) with numbers 1, 3 and 5 (1-single, 3-customary, 5-dominant). Scale for estimation of each algae taxa abundance: abundance presence of taxa in % of the visible field 1-single common > dominant > The saprobity of the river Tihaljina (Saprobic Index) was calculated on the basis of the list of indicator organisms, in order to assess the present water quality (according to Wegl, 1983) using the Pantle-Buck index (Pantle-Buck, 1955). A hierarchical cluster analysis comparing similarity in species structure and the relative abundance estimations of algae species (Bray-Curtis coefficient of similarity) (Clarke et al., 1990) was performed on the matrix of relative abundance estimations Physico-chemical parameters Existing data Monitoring of the water quality on the river Tihaljina is the responsibility of the Agency for the Adriatic Sea catchment (Mostar). Some data on water quality are also collected by Elektroprivreda HZ HB. In the periods of lower water level during summer the water quality can be lower, due to the presence of fecal pollution, which is connected to the fact that underground flow is likely to collect the wastewaters from the counties of Grude and Posušje. The causes for river pollution can also be found in agriculture, urbanization and the lack of wastewater treatment plants Additional sampling carried out during the project Additional sampling was done on in April 2008 at 5 sampling sites. To get more data about physico-chemical status of the river Tihaljina -Mlade the parameters presented in Table 2 were sampled: WWF Mediterranean Programme Office, June

32 Table 2 Parameters of additional sampling Parameter Geographical latitude Geographical longitude Date Temperature water ( o C) Turbidy (NTU) ph value m-alkalinity (mg CaCO 3 /l) Conductivity 20 o C (μs/cm) Suspend. solid (mg/l) Disolved oxygen (mg O 2 /l) Saturation (%) Total hardness (mg CaCO 3 /l) Carbonat hardness (mg CaCO 3 /l) COD- KMnO 4 (mg/l) Biological oxygen dem BPK 5 (mg/l) Amonium (mg N/l) Nitrate (mg N/l) Nitrite (mg N/l) Orthophosphate (mg P/l) Phosphorus (mgp/l) Sulphate (mg SO 4 /l) Ca-CaCO 3 (mg/l) Mg-MgCO 3 (mg/l) Natrium (mg/l) Silica (mg SiO 2 /l) Coliform bacteria in 100 ml of water Enterococcus faecalis Flow (m 3 /s) Analyses were done in the laboratory at Komunalno poduzeče Ljubuški. WWF Mediterranean Programme Office, June

33 6 RESULTS 6.1 Hydrology River flow data are essential for environmental flow assessment. Not only the amount, but also the timing, quantity and duration are important. Other priorities are an inventory of the ecologically relevant information that already exists in the country, and to quantify how hydrology impacts the river ecology. Daily flow data are the important starting point for assessing environmental flow. Monthly flow data are also a good alternative. But because the natural flow patterns vary so much from year to year, the data sets need to cover at least 20 years. Generally, for a statistical analysis of temporal variability and trends, long-term homogeneous time series are required. The study period with available hydrological data for the area should be divided into two sub-periods: that with a natural regime of flow, up to 1950, and that with an artificial one, since 1950, when the flood-prevention system had been built (i.e. the high water evacuation from upstream lake Nuga). The concrete-fast waterway (brzotok) built as part of this system was situated downstream close to the Tihaljina river source, so that the river system T-M-T is influenced during high water, as well as during maintaining operations. Water intakes for irrigation purposes are present along the whole section. The first one is situated immediately downstream of the Tihaljina source. HPP Pec Mlini has been functioning since The period is characterized as reference by the Study. Characteristic hydrological values were calculated on the basis of the daily average flows for the period of stations activity (Table 3) and for the common period for all the stations, e.g. the period Table 3 Available data for hydrological analyses No HS Water course Period 8 Peć Mlini Tihaljina Tihaljina source 9 Opeć Mlini Tihaljina Downstream 10 Tihaljina Tihaljina Klobuk Mlade Grabovo vrelo Mlade Grabovo vrelo Grabovo vrelo WWF Mediterranean Programme Office, June

34 As an example, the hydrograph for the Mlade at HS Klobuk, in 1987, is presented in Figure 8. Figure 8 Hydrograph of Mlade river at HS Klobuk, 1987 MIN Q = 3,35 m3/s, date 9.10; AV Q= 25,3 m3/s; MAX Q = 144 m3/s, date From Figure 8 we can see that minimum flows are common in summer time, while higher flows occur in winter and spring time. The hydrological calculations of the basic parameters needed for the GEP evaluation are given below for each hydrological station (Table 3 to Table 14). Detailed hydrological analyses are presented in Appendix 1-6. HS Peć Mlini source of Tihaljina* *Remark: water extraction for irragation is situated upstream of the station and it was not calculated in our analyses. There are no exact data on water quantity flowing through artificial channels and this accounts for the gaps in our analyses. Characteristic hydrological values and GEP methodology parameters shown in Table 4 and Table 5 have been calculated on the basis of the Tihaljina data. Table 4 Characteristic hydrological values, HS Peć Mlini-Tihaljina source Station No Qmin. meanqmin Q mean Q max. Period (m 3 /s) (m 3 /s) (m 3 /s) (m 3 /s) ,102 0,359 1,88 28, ,188 0,368 2,04 28,3 Table 5 GEP-methodology-based parameters calculated, HS Peć Mlini-Tihaljina source WWF Mediterranean Programme Office, June

35 HS Pec Mlini Tihaljina source, Period (1) average multiannual flow (Q ) 2,04 m 3 /s Probability, serie N=12 Gumbel Log Normal Frechet's Pearson III Log Pearson III (2) monthly-min low-flow 95% 0,339 0,308 0,335 0,304 0,309 exceedence probability ( Q.monthly 95 % ) m 3 /s (3) monthly-min low-flow 80% exceedence probability ( Q.monthly 80 & ) m 3 /s 0,388 0,375 0,377 0,387 0,376 HS Peć Mlini downstream, Tihaljina Table 6 Characteristic hydrological values, HS Peć Mlini-downstream, Tihaljina Station No Qmin. meanqmin Q mean Q max. Period (m 3 /s) (m 3 /s) (m 3 /s) (m 3 /s) 9 65, ,119 0,451 11,1 69,9 - peak ,119 0,478 12,8 69,9 Table 7 GEP-methodology-based parameters calculated, HS Peć Mlini-downstream HS Pec Mlini downstream, Tihaljina, Period (1) average multiannual flow (Q ) 12,8 m 3 /s Probability, series N=12 Gumbel Log Normal Frechet's Pearson III Log Pearson III (2) monthly-min low-flow 95% 0,277 0,319 0,393 0,320 exceedence probability ( Q.monthly 95 % ) m 3 /s (3) monthly-min low-flow 80% exceedence probability ( Q.monthly 80 & ) m 3 /s 0,552 0,521 0,527 0,542 0,521 WWF Mediterranean Programme Office, June

36 HS Tihaljina, Tihaljina Table 8 Characteristic hydrological values, HS Tihaljina, Tihaljina Station No Qmin. meanqmin Q mean Q max. Period (m 3 /s) (m 3 /s) (m 3 /s) (m 3 /s) ,119 0,660 16, ,119 0,671 17,6 128 Table 9 GEP-methodology-based parameters calculated, HS Tihaljina HS Tihaljina, Tihaljina, Period (1) average multiannual flow (Q ) 17,6 m 3 /s Probability, serie N=13 Gumbel Log Normal Frechet's Pearson III Log Pearson III (2) monthly-min low-flow 95% 0,266 0,287 0,365 0,288 exceedence probability ( Q.monthly 95 % ) m 3 /s (3) monthly-min low-flow 80% exceedence probability ( Q.monthly 80 & ) m 3 /s 0,584 0,507 0,514 0,572 0,507 HS Klobuk, Mlade Table 10 Characteristic hydrological values, HS Klobuk, Mlade Station No Qmin. meanqmin Q mean Q max. Period (m 3 /s) (m 3 /s) (m 3 /s) (m 3 /s) ,26 4,06 25, ,77 4,14 27,5 214 Table 11 GEP-methodology-based parameters calculated, HS Klobuk HS Klobuk, Mlade, Period (1) average multiannual flow (Q ) 27,5 m 3 /s Probability, serie N=12 Gumbel Log Normal Frechet's Pearson III Log Pearson III (2) monthly-min low-flow 95% 3,14 3,03 3,32 2,69 3,03 exceedence probability ( Q.monthly 95 % ) m 3 /s (3) monthly-min low-flow 80% exceedence probability ( Q.monthly 80 & ) m 3 /s 3,78 3,77 3,79 3,76 3,75 WWF Mediterranean Programme Office, June

37 HS Grabovo vrelo, Mlade Table 12 Characteristic hydrological values, HS Grabovo vrelo Remark: Average flow, absolute minimum flow and mean minimum flow, and mean flow, profile Grabovo vrelo mouth, Mlade, are calculated on the basis of daily scores Q GRABOVO VRELO MOUTH (MLADE) = Q HS KLOBUK(MLADE) + Q HS GRABOVO VRELO (GRABOVO VRELO) Station No Qmin. meanqmin Q mean Period (m 3 /s) (m 3 /s) (m 3 /s) ,77 4,24 30, ,77 4,14 29,8 Table 13 GEP-methodology-based parameters calculated, HS Grabovo vrelo Profile Grabovo vrelo mouth, Mlade, Period (1) average multiannual flow (Q ) 29,8 m 3 /s Probability, serie N=13 Gumbel Log Normal Frechet's Pearson III Log Pearson III (2) monthly-min low-flow 95% 3,15 3,04 3,33 2,71 3,04 exceedence probability ( Q.monthly 95 % ) m 3 /s (3) monthly-min low-flow 80% exceedence probability ( Q.monthly 80 & ) m 3 /s 3,79 3,77 3,79 3,77 3,77 Guaranteed ecological flow GEP The GEP was calculated for all hydrological stations in the selected section of the river Tihaljina -Mlade, according to data covering the period The results of the GEP calculation for the hydrological stations are presented in Table 14. WWF Mediterranean Programme Office, June

38 No Station average flow Q m 3 /s 8 Peć Mlini Tihaljina source 0,1 Q m 3 /s 0,15 Q m 3 /s 0,25 Q m 3 /s monthlymin low-flow 95% exceedence probability ( Q min.monthly 95 % ) m 3 /s monthlymin low-flow 80% exceedence probability ( Q min.monthly 80 & ) m 3 /s GEP Cold season Q m 3 /s GEP Warm season Q m 3 /s 2,04 0,204 0,306 0,510 0,309 0,376 0,306 0,376 9 Peć Mlini downstream 12,08 1,21 1,81 3,02 0,320 0,521 1,21 1, Tihaljina 17,6 1,76 2,64 4,40 0,365 0,514 1,76 2,64 Klobuk 27,5 2,75 4,13 6,88 3,03 3,75 3,03 4,13 12 Grabovo vrelo (Mlade) 29,8 2,98 4,47 7,45 3,04 3,77 3,04 4,47

39 6.2 River ecology Introduction A habitat (from an ecological point of view) is an area inhabited by a particular species or the physical environment that surrounds (influences and is utilized by) a species population.. The habitat in combination with the biological community (Biocoenosis) is a higher unit which is called ecological system (Ecosystem). The diversity of a certain habitat is closely linked to its geographical location, topography, geological, climatic and hydrographical circumstances and human influences. Human has activities have destroyed many habitats in rivers. With the increase in human population and human activities, habitats are being destroyed ever more rapidly on a global scale. Therefore, the efforts of the international community and a number of associations to protect and preserve the diversity of habitats, as well as the diversity of flora and fauna, are fundamental. It is known that Bosnia and Herzegovina is a country with diverse habitats and ecosystems. Many of these habitats are endangered and some of them have already been destroyed. Many organisms are endangered and some of them are considered to be extinct in this area. In BiH there is no list of endangered habitats. Because the river Trebižat is close to Croatia, the habitat classification from Croatia was used. Habitats noted as endangered in Croatia are shown in Table 15 (According to: Antonić, O.; Kušan, V.; Bakran-Petricioli, T.; Alegro, A.; Gootstein-Matočec, S.; Peternel, H.; Tkalčec, Z. (2005): Habitat classification of the Republic of Croatia. Drypis 1/1 : 1-12.) Explanation of abbreviations from table 15 NATURA NATURA 2000 is an ecological network of the European Union which includes areas that are important for the preservation of endangered species and habitat types. This program, which is the basic protection of nature in EU, emerges from a Council Directive on the conservation of wild birds (Council Directive79/409/EEC) and a Council Directive on the conservation of natural habitats and wild fauna and flora (Council Directive 92/43/EEC). PHYSIS database on habitat types created by the Institut Royal ales Sciences Naturelles de Belgique. NKS National habitat classification is a database on habitats of the Republic of Croatia. WWF Mediterranean Programme Office, June

40 Table 15 Endangered habitats Habitat type NATURA PHYSIS NHC Pannonian salt grassland C.37 Juniper formations on heaths D1215 Petrifying springs 7220* A34 Bog birch woods on sphagnum 91D0* 44.A12 E327 peat bog Oleander galleries 92D D322 Mediterranean and stone pine E8210 woods and plantations Travertine-forming riparian A35 communities Travertine-forming waterfall vegetation A36 Complex NATURA PHYSIS NHC Estuaries ; 13.2 K1 Coastal lagoons 1150* 21 K2 Large shallow inlets and bays K3 In the area of the Tihaljina - Mlade several habitat types can be treated as endangered. These include: Calcareous sources, such as the spring of Tihaljina in Peć Mlini and the spring of Modro oko; Travertine-forming riparian communities that are common in the river Trebižat; Travertine-forming waterfall vegetation. For all the above-mentioned possibly endangered habitats there are no data about their flora and fauna, or the data are very old (from 1963). The Tihaljina spring is a revolving type spring, with strong water aeration and rocky ground. Limestone wells are a specific form from which, during rainy periods, a great quantity of water pours out, thus creating a strong, sudden stream, while during dry periods they dry out. This type of habitat is considered as a unique ecological unit. Travertine-forming riparian communities The river Trebižat is well-known for travertine formation. The formation of calcareous sinter or travertine is common for karst rivers and results in the formation of certain geomorphologic shapes, especially waterfalls. A development of calcareous sinter is the formation of calcareous barriers and waterfalls on the Trebižat River. The community of calcareous creators is very sensitive because it depends on a combination of conditions, and especially on fresh clean water. The creation of calcar is a complex process involving various physical, chemical and biotic factors. Limestone particles are exuded more intensively as the area of the water surface in contact with the atmosphere grows. WWF Mediterranean Programme Office, June

41 CaCO 3 is actually made in areas of intensive turbulence because of the greater area of contact between air and water and the varying pressure between CO2 in the air and water. Here the CO2 breaks away from the H2O and thus the balance of reaction is disturbed towards a higher concentration of carbonates, thus producing particles of CaCO3. 2 HCO 3 - CO CO 2 + H 2 O Apart from favourable physical conditions in the Trebižat River there are also favourable temperature conditions. The temperature of the water is almost always higher than its sedimentation limit temperature. In summer the temperature of the water is always higher than its sedimentation limit temperature of 14 C. Lower temperatures at that time occur only in the spring area or in places where there are wells in the river flow. Thus, sedimentation fails only in those habitats. Calcareous layers grow slowly and occur in those parts of the river or the spring where splashing and aeration of water is very intensive. In the winter the temperature is not suitable, so there is no calcareous creation in those conditions. However, for the creation of calcareous layers the presence of certain organisms is necessary, especially hygrophyte and hydrophytes moss and algae. In cases of strong splashing, aeration and streaming of water, excreted particles are carried away by the current down to places where they begin alluvial sedimentary processes. That happens in very fast waters (when the speed is higher than 3.5 m/s). In areas of slower flow the vegetative bodies of organisms keep the excreted particles of calcium carbonate and create calcareous layers, which grow along with the growth of calcareous organisms. The most optimal speed is 1-2 m/s, where the biggest number of calcareous organisms is retained. Together with the splashing, aeration and streaming of water, and necessary alkalinity and temperature of water, the light also influences the creation of calcar. In younger calcareous creations, which are exposed to light, heliophilous vegetation develops, which has a more or less friable sod. This occurs at springs and in the upper flows of rivers where the temperature is not suitable, thus the calcareous creations are formed very slowly. Old calcareous barriers, which are the most developed forms of calcareous layers, are sometimes covered in higher vegetation, which overshadows the calcareous vegetation habitats. Thus the old barriers develop in downstream flows, and the growth of calcareous layers is much more intense. With the growth of calcareous layers, the ecological situation changes. The consequence is populations of different biocoenosis which are in a mutual successive relationship. Some animals also participate in the creation of calcareous layers, not only plants, moss or algae (Matoničkin & Pavletić 1972). At big old barriers in natural vegetation succession, woody species occur, mostly willow and alder which can destroy the barriers with their roots. These destructive effects have been known to change the water regime, creating a periodic insufficient water flow. When out of water, calcareous organisms die, and the barriers can cave in (Nikolić 2006). The recommended safety measures are to maintain a sufficient constant flow of clean fresh water and prevent the covering of the barrier by woody species Fish The Adriatic basin is famous for its high level of endemism (44 Mediterranean, 40 Adriatic and 18 Croatian endemic plants), which is a direct consequence of the variety WWF Mediterranean Programme Office, June

42 of karst habitats. Freshwater fish are one of the most endangered types of vertebrates. 89 species are included in the Red book of freshwater fish in Croatia. The colonisation by allochtonus species, pollution, water flow regulations and destruction of habitats, building dams, irrigation, extraction of water for domestic use and industry, as well as uncontrolled fishing, have had the most negative influence on freshwater fish. According to information on the qualitative and quantitative content of ihtiofauna of the Trebižat River from Bogut, I., Pavličević, J., Ivanković, S., Petrović, D., 2003, the following fish species are recorded in the river Tihaljina i Mlade: Table 16 Fish species of the Tihaljina river type of fish Brown trout Salmo trutta m. fario Rainbow trout Oncorhynchus mykiss White chub Leuciscuc cephalus albus Sraper Leuciscus svallize Butterwort Rutilus rubilio rubilio Scardinius plotizza Scardinius erytrophthalmus scardofa Nose-carp Chondrostoma kneri Carp Cyprinus carpio Tench Tinca tinca The Red book of Croatia VU - VU VU VU DD EN EN - Table 17 Fish species of the Trebižat river (Mlade part) type of fish Brown trout Salmo trutta m. fario Neretva dentex trout Salmothymus obtusirostris oxyrhynchus Rainbow trout Oncorhynchus mykiss White chub Leuciscuc cephalus albus Sraper Leuciscus svallize Nose-carp Chondrostoma kneri The Red book of Croatia VU CR* - VU VU EN* WWF Mediterranean Programme Office, June

43 Butterworth Rutilus rubilio rubilio Scardinius plotizza Scardinius erytrophthalmus scardofa Tench Tinca tinca Carp Cyprinus carpio Spotted minnow Phoxinellus adspersus VU DD - EN VU* With every mentioned type there is a category of endangerment, according to Mrakovčić, M., et all. (2007): the Red book of freshwater fish in Croatia (National Institute of Environment Protection, Zagreb). CR critically endangered there is an extremely high risk of extinction. EN endangered there is an extremely high risk of extinction; VU risk there is a high risk of extinction; DD not known enough there isn t enough information for the assessment of the risk of extinction (population and distribution state). Endemic species are labeled with a star (*) beside the category. Endemic species are especially sensitive and usually lack the capacity to adapt to changes in external factors. They are mostly spread in former glacial refugia and closely connected to the environment where they live. In the upper part of the Tihaljina river the habitats are characterised by high current velocity and low water temperature. The concentration of oxygen is high, and there is almost no water pollution. This area is populated with brown trout ( Salmo trutta m. fario). They spawn from October to January, in cold rather than in warm waters. Females then make an egg-shaped cavity of 20-50cm and lay around 1000 eggs per kg of their weight,. The eggs are 4-5mm big, yellow-red or orange. When they grow, the fish travel upstream. Then, the downstream current velocity is also high, the water is rich with oxygen, but with a rather higher temperature than the river source. In this river section, white chub, scraper, scardinius plotizza and rainbow trout are common. Different fish species which live in different sections of the river can be sorted according to the way they spawn: on gravel or plants. For those that spawn on plants the so-called soft progress and hard water plants retrogress are important. Myriophyllum, Ceratophyllum, Ranunculus fluviatilis and different types of pondweed (Potamogeton) are representatives of soft water plants. Hard water plants are cane (Phragmites), rush (Typha), common rush (Juncus). Floods are extremely important biological events for every river and related area. During floods, wide canals (side), sleeves, isles and swamps are created by erosion processes and there is a great diversity of habitats in which animals eat, hide and breed. Floods help the preservation of biological diversity, enabling animals and plants to take new as well as current habitats. Floods are important for fish breeding WWF Mediterranean Programme Office, June

44 and feeding: during high water levels, they migrate massively from the river bed to the new flooded areas (Mrakovčić 2007). None of the freshwater fish present in Trebižat has been legally protected in BiH. Practically, the protection of the majority of species can be implemented only by the protection of their habitats Invertebrates Representatives of the karst spring among the spineless, the so called krenobionti, are some crustaceans (Fontogammarus dalmatinus, Gammarus balcanicus, Gammarus Fossarum, Niphargus castellanus), insect larva from the groups Diptera (Atherix spp.), Ephemeroptera (Baetis rhodani, Ecdynurus spp., Ephemerella spp.), Odonata (Cordulegaster), Plecoptera (Leuctra spp., Protonemura spp.) and Trichoptera (Drusus synagapetus), water ambrosia beetles ( Helmis spp.), turbellaria (Crenobia alpina), snails Ancylus fluviatilis and Belgrandiella, Bithynia, Dalmatella, etc.(matoničkin & Pavletić 1972) Macrophytes For the distribution of water and swamp plant communities, the most important factor is water, and especially the water level in the ecosystem (Fernández Aláez and associates 1999., Jasprica and associates. 2003). In the tables we mark the species which are in the Red book of BiH, (according to Šilić Č., 1996). Species are labelled in accordance with International Union for Conservation of Nature (IUCN) standards. The system of evaluating endangerment consists of the following categories: o Ex extinct-vanished species. This category includes the species which have not been found during the repeated search at or near the location where they had been found before; o Ex? probably extinct species; o E very endangered species. This category includes the species which are so endangered that they could easily become extinct or vanish if the harmful influences remain; o V endangered and vulnerable species. Species which live in habitats with an ecological balance very sensitive to even the smallest humanogene interventions (e.g. warm springs, frosters, peat bogs, ponds, etc.). A continuous negative influence to the habitat unavoidably places the given species in category E ; o R rare or potentially endangered species. They are the rare and scarce species which are not directly endangered, but could easily become so. Those are the species living in small areas, particularly endemic and relic species; o K insufficiently known species. This category includes the species which are assumed to belong to one of the categories, but there is no information for an accurate categorization. The results of sampling of macrophytes are presented in Tables PEĆ MLINI TIHALJINA SOURCE Table 18 T1 Peć Mlini Tihaljina source WWF Mediterranean Programme Office, June

45 Tihaljina spring in Peć Mlini Red list B&H Plant species: Carex vulpina L Carex divulsa Stokes Rumex obtusifolius L. Lysimachia vulgaris L. Campanula fenestrellata FEER Trifolium fragiferum L. Arabis verna (L.) R. Br. Hepatica nobilis L. Rorippa amphibia (L.) Bess. Sedum sp. Polypodium vulgare L. Tussilago farfara L. Scutellaria galericulata L. Carex elata All. Sium erectum Huds. Galium palustre L. Mentha pulegium L. Polystichum lochitis (L.) Roth Papaver rhoeas L. Silene sp. Fraxinus angustifolia Vahl. Salix alba L. Sedum album L. Opsponax chironium (L.) KOCH Coronilla emerus spp. emeroides L. Umbilicus horizontalis L. Parietaria judaica L. Arabis turrita L. Asplenium trichomanes L. Adiantum capillus veneris L. Clematis vitalba L. Populus alba L Alnus glutinosa L. Ficus carica L. Ceterach officinarum DC. V R V On a rocky bottom, individually in smaller turfs, the water moss Fontinalis antipyretica occurs. The Fontinalis antipyretica moss is an important species near spring waters where it builds the distinctive biological community Fontinaletum antipyreticae (Jasprica 2001). That is a community of very polymorph moss on the rocks by the springs where the water is fast. Approx. 0,5 m long turfs detach by the water flow and can be found floating on the water surface. By the river shore, on the grounds that are periodically flooded or are humid because of the height of underground waters, there is a narrow zone of flood forests which include: Willow (Salix alba), poplar (Alnus glutinosa), ash (Fraxinus angustifolia) and others. In shallow water by the shore, where the river bed is dominated by gravel, Sium erectum, Mentha pulegium, Rumex obtusifolius, Rorippa amphibia develop. On the WWF Mediterranean Programme Office, June

46 rocks by the river, which are exposed to the light and have enough humidity, Campanula frenestellata, Hepatica nobilis, Parieteria judaica, Lysmachia vulgaris, Umbilicus horizontalis develop. On half-caves and caves next to the spring, which are in the shadow, the following species are noted: Adiantum capillus veneris, Asplenium trichomanes, Polystichum lochitis i Polypodium vulgare. Species noted on this site are characteristic of the mentioned habitat types. PEĆ MLINI DOWNSTREAM Table 19 T2 Peć Mlini downstream Peć Mlini Downstream Red list B&H Plant species: Veronica anagallis aquatica L. Euphorbia sp. Cornus mas L. Carex vesicaria L. Clematis vitalba L. Parietaria judaica L. Cicerbita muralis (L.) WALLR. Lathyrus niger (L.) BERNH Geranium lucidum L. Poa bulbosa L. Sedum sp. Ficus carica L. Ranunculus trichophylus Chaix Sium latifolium L. Potamogeton crispus L. The broomrape family is very rare in this area. Species like Ranunculus trichofilus, Sium latifolium and Potamogeton crispus occur individually and are noted near riverbanks when water level is the lowest. As there are no higher plants in the river, the role of primary producer is taken by algae. A lack of plentiful water vegetation can be explained by the type of river bottom (rocky), the banks (steep and rocky) and the high flows. All of that makes it impossible for water vegetation to take root in the ground. Recorded species are on the higher parts of banks which are periodically splashed. BLUE EYE SPRING Table 20 T3 Blue eye spring (Modro oko) Blue eye spring Red list B&H Plant species: Rhamnus catarthica L. Aristolochia rotunda L. R WWF Mediterranean Programme Office, June

47 Seseli annuum L. Galium pumilum Murr. Astragalus allyricus BERNH. Ranunculus parviflorus L. Ajuga reptans L. Carex vulpina L Arabis hirsuta (L.) Scop. Clematis viticella L. Phragmites australis (Cav.) Trin. Mentha pulegium L. Mentha aquatica L. Asplenium petrarchae (Guer.) DC. Thelypteris palustris Schott Pteridium aquilinum (L.) Kuhn Limodorum abortivum (L.9 Swartz Potamogeton pectinatus L. Edraianthus graminifolius (L.) DC. Galium lucidum All. V E The Blue eye well, which forms a small creek, is a left confluent of the Trebižat River. The water is transparent and the bottom can be seen clearly. Water plant species recorded included, at a deeper level, Potamogeton pectinatus. In shallow water Mentha pulegium, Mentha aquatica and Ajuga reptans were recorded near the banks. At the higher level of the banks we found Phragmites australis, Asplenium petrarchae, Thelypteris palustris and others. A little bit further, on flooded meadows, which were under water (where the ground is soft and muddy) Edraianthus graminifolius, Galium lucidum, Limodorum abortivum were recorded. At this locality the anthropogenic influence is almost insignificant, and the vegetation is specific for this ecosystem. THE KAVASBAŠA BRIDGE Table 21 T4 The Kavasbaša Bridge The Kavasbaša Bridge Plant species: Eleocharis palustris (L.) R.S. Lythrum scalicaria L. Galium palustre spp. lanceolatum UECHTR Ajuga reptans L. Ajuga genevensis L. Thymus pulegioides L. Lycopus exaltatus L. f. Rumex obtusifolius L. Equisetum fluviatile L. Equisetum palustre L. Centaurium pulchelum (Sw.) Druce Plantago maior L. Ranunculus repens L. Carex pendula Hudson Red list BiH WWF Mediterranean Programme Office, June

48 Iris pseudacorus L. Phragmites australis (Cav.) Trin. Ranunculus fluitans LAM. Holoschoenus vulgaris Link Schoenoplectus lacustris (L.) Pala Alisma plantago-aquatica L. Sium latifolium L. Juncus articulatus L. Downstream from the Kavabaša Bridge on the right side, in shallow water up to 1m high and with a sandy bottom, swamp vegetation has developed, mainly from the Phragmitetalia family. Communities of this family present developed vegetation with a high number of flora species. Here swamp vegetation developed better than water vegetation, because the water level was very high and the river flow was very fast. At this locality, the species Iris pseudacorus, which in BiH is otherwise recorded only in Hutovo Blato, was especially noted. According to the ecological conditions and habitat type, the recorded flora species are characteristic. GRABOVO VRELO Table 22 T5 Grabovo vrelo Grabovo vrelo Red list B&H Plant species: Equisetum maximum LAM. Carex vesicaria L. Papaver rhoeas L. Carex vulpina L Anthemis arvensis L. Myriophyllum verticillatum L. Nymphaea alba L. Sium latifolium L. Veronica beccabunga L. Myriophyllum spicatum L. Rorippa amphibia (L.) Pala Potamogeton lucens L. Nuphar luteum Sibth. et Sm. Alisma plantago-aquatica L. Alisma gramineum Lej. Phragmites australis (Cav.) Trin. Cyperus longus (L.) Juncus articulatus f. palidiflorus L. Holoschoenus vulgaris Link. Eriophorum latifolium Hoppe Scirpus litoralis (Schrad.) Palla Scirpus lacustris (L.) Palla Briza media L. Oenanthe aquatica (L.) Poir. Carex acutiformis Ehrh. V V WWF Mediterranean Programme Office, June

49 Carex paniculata L. Juncus articulatus L. Gratiola officinalis L. Eleocharis palustris (L.) R. et S. Lysimachia nummularia L. Galium palustre L. Mentha aquatica L. Lycopus europaeus L. Lythrum scalicaria L. Artemisia annua L. Mentha pulegium L. Calystegia sepium (L.) R. Br. Veronica anagallis aquatica L. Asparagus acutifolius L. Symphytum officinalis L. Rumex pulcher L. Ruscus aculeatus L. Zannichellia palustris L. Polygonum amphibium var. terrestre L. Typha latifolia L. Iris pseudacorus L. V V At this locality the river bed is sandy. In deep water, where the current velocity was low, some types of storks occur periodically: Myriophyllum, Nuphar lutea and Nymphaea alba. These species take small areas of the river. In the deepest parts, regardless of the current, there is a complete underwater meadow of pondweed. This is especially abundant at times of low water levels. Swamp vegetation in which Phragmites australis dominates is very abundant and developed here, as the slower current of water and light suits it and here there is no woody vegetation on the banks to create shadow. Conclusions: The water regime determines the species composition of the flora (including macrophytes) in the studied area of the river Tihaljina and Mlade. According to the structure of the plant communities, the aquatic vegetation in the river Trebižat (Tihaljina and Mlade) does not show serious degradation trends, despite the fact that the area is influenced by multiple human impacts Phytobenthos Species composition The analysis of phytobenthos showed a high number of species in the sampling sites included in the study (Table 23), with Bacillariophyceae as the largest group. In addition, in the research of algae on the travertine barriers of the the Krka river in Slovenia, Bacillariophyceae was the most numerous group (Vrhovšek et al., 1996; WWF Mediterranean Programme Office, June

50 Krivograd Klemenčič et al., 2004). In total, 69 taxa and 5 algal classes were identified in all five sampling sites. In the number of identified taxa, diatoms prevailed with 58 taxa, followed by Cyanophyceae with 5, Chlorophyceae with 3, Florideophyceae with 2 and Zygnematophyceae with 1 takson. Customary (relative abundance=3) found species were: Gloeocapsa sp. (T2), Heteroleibleinia sp. (T1), Phormidium sp. (T1, T2), Achnanthes sp.1 (T1), Nitzschia fonticola (T1) and Ulothrix sp. (T2). N. fonticola was also a common species on the travertine barriers of the Krka river (Krivograd Klemenčič et. al., 2004). In all five samples, the following species were recorded: Achnanthes sp.1, Cymbella silesiaca, Gomphonema angustum and Nitzschia dissipata. Most of the taxa belonged to the Navicula (10) and Nitzschia (10) genera. The lowest number of taxa (20) was determined in the sampling sites T1 and T3 and the highest one (40) at the sampling site T4. Red algae Audouinella chalybea and Bangia atropurpurea (Rhodophyta, Florideophyceae) are occasionally found on travertine. Both require turbulent water. Filaments of A. chalybea are sometimes found growing on the surfaces of oncoids and stream crusts in the shaded watercourses of Europe (Pentecost, 2005). We determined A. chalybea in the sampling site T4 and B. atropurpurea in the sampling site T2. Gloeocapsa species are to be found on a wide range of travertine, because they remain dry for much of the year (Pentecost, 2005). Also Pleurocapsa is widely distributed on travertines in Europe and frequently reported. Gloeocapsa sp. was a common species in the sampling site T2, Pleurocapsa minor was determined in the sampling sites T2 and T4. The filamentous cyanobacteria are among the most frequent colonisers of active travertine surfaces (Pentecost, 2005). Phormidium sp. was a common species in the sampling sites T1 and T2 and Heteroleibleinia was a common species in the sampling site T1. Filamentous Zygmemales are common on travertine; they include taxa belonging to the genera Mougeotia, Spirogyra and Zygnema. All of these filamentous algae are also known from non-travertinedepositing waters (Pentecost, 2005). We determined the species Mougeotia sp. in the sampling site T2. In the samples from the Tihaljina river we recorded 58 diatom taxa, among them 24 taxa are frequently recorded from active travertine (they are marked in Table 23 with an asterisk). Some of these diatoms are: Achnanthes lanceolata, A. minutissima, Amphora ovalis, Cocconeis pediculus, C. placentula, Cymatopleura solea and Nitzschia palea. Nitzschia fonticola was a common species in the sampling site T1, but it was nor recognized as travertine typical species by other authors (Pentecost, 2005). The initial stages of travertine formation as a result of morphological, biological, and chemical factors are (i) moss settling on small ridges in the creek courses, (ii) epiphytes (diatoms and cyanobacteria) settling on the moss surface, (iii) micrite particles resuspending from lake bottoms and being trapped on the mucous excretions by bacteria and diatoms, and (iv) inorganic calcite precipitating as sparite at nucleation sites provided by these crystal seeds (Emeis, 1987). The Saprobic Index (Table 24) ranged from 1.46 (T1) to 1.62 (T4). According to the results of the Saprobic Index, we can classify the Tihaljina River as at an oligosaprobic (unpolluted) level at the sampling site T1 and from an oligosaprobic (unpolluted) to β-mesosaprobic (moderate impurity) level at the other four sampling sites. WWF Mediterranean Programme Office, June

51 Table 23 Algal species list with abundance estimations from the river Tihaljina, * Diatoms frequently recorded from active travertines by Pentecost (2005) Taxa Sap. value Sampling sites T1 T2 T3 T4 T5 PROKARYOTA CYANOPHYTA CYANOPHYCEAE Calothrix sp. o 1 1 Gloeocapsa sp. o 3 Heteroleibleinia sp Phormidium sp. o-a Pleurocapsa minor Hansgirg 1 1 EUKARYOTA HETEROKONTOPHYTA BACILLARIOPHYCEAE Achnanthes delicatula (Kützing) Grunow 1 *Achnanthes lanceolata (Brébisson) Grunow o 1 1 *Achnanthes minutissima Kützing o Achnanthes sp.1 b Achnanthes sp.2 b 1 Achnanthes sp.3 b 1 Amphora libyca Ehrenberg 1 *Amphora ovalis Kützing o-b 1 1 Amphora pediculus (Kützing) Grunow o-b *Cocconeis pediculus Ehrenberg b 1 1 *Cocconeis placentula Ehrenberg o Cyclotella sp. o-b 1 1 Cymatopleura elliptica (Brébisson) W.Smith b 1 *Cymatopleura solea (Brébisson) W. Smith b 1 *Cymbella affinis Kützing o *Cymbella cistula (Ehrenberg) Kirchner o 1 1 *Cymbella microcephala Grunow o Cymbella naviculiformis Auerswald o 1 Cymbella prostrata (Berkeley) Cleve b 1 Cymbella silesiaca Bleisch o-b Cymbella sinuata Gregory o-b 1 *Denticula tenuis Kützing o *Diatoma vulgaris Bory b 1 1 Fragilaria capucina Desmazières o-b Fragilaria pinnata Ehrenberg o 1 *Fragilaria ulna (Nitzsch) Lange-Bertalot b 1 1 Frustulia vulgaris (Thwaites) De Toni b 1 1 *Gomphonema angustatum (Kützing) Rabenhorst b 1 *Gomphonema angustum Agardh o *Gomphonema olivaceum (Hornemann) Brébisson b Gyrosigma attenuatum (Kützing) Rabenhorst b Gyrosigma nodiferum (Grunow) Reimer 1 1 Melosira varians Agardh o-b 1 *Meridion circulare (Greville) C. A. Agardh o 1 Navicula capitatoradiata Germain b 1 WWF Mediterranean Programme Office, June

52 Taxa Sap. value Sampling sites T1 T2 T3 T4 T5 *Navicula cryptotenella Lange-Bertalot o Navicula mutica Kützing o 1 Navicula placentula Ehrenberg b 1 *Navicula pupula Kützing b 1 Navicula radiosa Kützing o-b 1 Navicula sp. b *Navicula tripunctata (O. F. Müller) Bory o-b Navicula trivialis Lange-Bertalot *Navicula viridula (Kützing) Ehrenberg b-a 1 Neidium binodis (Ehrenberg) Hustedt 1 1 Neidium bisulcatum (Lagerstedt) Cleve 1 Neidium sp *Nitzschia amphibia Grunow *Nitzschia dissipata (Kützing) Grunow o Nitzschia fonticola Grunow o Nitzschia gracilis Hantzsch o-b 1 1 Nitzschia heufleriana Grunow 1 1 Nitzschia linearis (Agardh) W. Smith o-b 1 *Nitzschia palea (Kützing) W. Smith b-a 1 Nitzschia recta Hantzsch o-b 1 Nitzschia sigmoidea (Nitzsch) W.Smith b-a 1 *Nitzschia sinuata var. tabellaria Grunow o 1 1 Surirella angusta Kützing o-b 1 CHLOROPHYTA CHLOROPHYCEAE Trentepohlia aurea (L.) Martius 1 Ulothrix sp. b 3 Ulothrix zonata Kützing o 1 ZYGNEMATOPHYCEAE Mougeotia sp. o-b 1 RHODOPHYTA FLORIDEOPHYCEAE Audouinella chalybea (Lyngbye) Fries b-a 1 Bangia atropurpurea Agardh o 1 Number of taxa Saprobic index Table 24 Number of indicator taxa for single saprobic level T1 T2 T3 T4 T5 oligosaprobic oligo-betamezo saprobic beta mezosaprobic WWF Mediterranean Programme Office, June

53 betamezo-alfamezo saprobic / 1 / 3 / oligo-alfamezo saprobic 1 1 / 1 / Cluster analysis The dendrogram (Figure 9) shows the largest similarity between the sampling sites T2 and T4 and the most different one at sampling site T3. 0,8 0,75 0,7 0,65 0,6 0,55 0,5 0,45 0,4 T2 T4 T5 T1 T3 Figure 9 Bray-Curtis coefficient of similarity for the sampling sites in the Tihaljina river The results of the Bray-Curtis coefficient of similarity, especially the differences in species composition at sampling site T3, coincide with the increasing organic pollution on sampling site 3 and the fact that this sampling site is the tributary of the Tihaljina river. WWF Mediterranean Programme Office, June

54 Figure 10 1-Gloeocapsa sp., 2-Phormidium sp., 3-Achnanthes sp., 4- Ulothrix sp., 5-Nitzschia fonticola 6.3 Physico-chemical parameters According to the Directive of the European Parliament and of the Council 2000/60/EC, which establishes a framework for community action in the field of water policy, Annex 5, Article the quality of the physical chemical characteristics of the surface waters, and the water quality at the given localities is referred to as good status, meaning: - Temperature oxygen balance, ph, acid neutralizing capacity and salinity do not reach levels outside the range established to ensure the functioning of the type specific ecosystem and the achievement of the values specified above for the biological quality elements. - Nutrient concentrations do not exceed the levels established to ensure the functioning of the ecosystem and the achievement of the values specified above for the biological quality elements. WWF Mediterranean Programme Office, June